InxGayAl1-x-yN (0<=x<=1, 0<=y<=1) is one of the materials of choice for fabricating short wavelength light-emitting devices. In recent years, researchers worldwide have developed many novel InGaAlN-based light-emitting devices, such as blue, green, and white light-emitting diodes (LEDs) and violet semiconductor lasers. Meanwhile, InGaAlN is also a good material for manufacturing high-performance electronic devices.
Among exiting technologies, methods for fabricating InGaAlN materials on sapphire and SiC substrates are known to the public. For example, Japanese patent JP2737053 disclosed a method for fabricating GaN materials on a sapphire substrate; and U.S. Pat. No. 5,686,738 disclosed a method for fabricating GaN materials on a SiC substrate. Based on these publicly available technologies, one can fabricate high-quality InGaAlN materials. However, since SiC substrates are very expensive, using SiC substrates to fabricate InGaAlN can incur high costs. Sapphire is also costly. Furthermore, sapphire is an insulator and is difficult to process. An InGaAlN device fabricated on a sapphire substrate cannot have a vertical electrode configuration. As a result, fabricating InGaAlN devices on a sapphire substrate can be complex and costly. Silicon, being a mature semiconductor material, is not only cheap, but also easy to control in terms of conduction type and resistivity. Moreover, techniques for processing silicon are fairly mature. Using silicon to fabricate InGaAlN materials can significantly reduce the associated costs. However, silicon and InGaAlN materials exhibit considerable lattice mismatch and thermal mismatch. Consequently, InGaAlN materials fabricated on silicon are prone cracking and cannot be used to fabricate high-performance light-emitting or electronic devices. Paper (Phys. stat. sol. (a) 188, 155 (2001)) provided a method for using SiN patterning and masking on a substrate, which can reduce the amount of cracking. However, this method is unsuitable for volume production due to its complexity. Paper (Appl. Phys. Lett. 78, 288 (2001)) provided a method for lateral confined epitaxy, which improves stress relief by forming grooves. However, this paper concluded that the crack-free area of a 0.7 μm thick GaN material grown on a (111) silicon substrate cannot exceed 14.3 μm. A typical light-emitting device requires a device area greater than 100×100 μm2 due to the need for fabricating ohmic electrodes. Therefore, the methods disclosed by these published papers cannot be used to fabricate efficient light-emitting devices.